2 ARSENATE OF LEAD AGAINST TOBACCO HOENWORMS. 



NECESSmr AND ADVANTAGES OF THE USE OF AN INSECTICTOE. 



The way in which the scarcity of labor tended to bring about the 

 use of an insecticide upon tobacco has already been explained. In 

 addition to this necessity of using insecticides, the much greater 

 efficiency of a good application of an insecticide is another strong 

 argument in its favor. Hand-worming, even of the best, has many 

 objections; for instance, eggs are not picked off, many small worms 

 are overlooked on account of their small size, and, lastly, during the 

 hot hours of the day large worms crawl down into the " ruffles " near 

 the bases of the leaves and a considerable number are thus over- 

 looked. On the other hand, a thorough application of an insecti- 

 cide will kill practically every homworm — except those very nearly 

 full grown — within two or three days, and will also continue to kill 

 the young worms that hatch several days after the application. In 

 short, hand-picking has only an immediate effect in lessening the 

 worms, whereas the application of an insecticide usually continues to 

 kill over a period of several days. Cheapness is another point very 

 greatly in favor of an insecticide as compared with hand-picking. 

 The cost of keeping an acre of tobacco hand-wormed in a year when 

 worms are plentiful is variously estimated at from $6 to $10. A like 

 number of worms can be killed with an insecticide at a cost of not 

 more than $2 or $3 an acre — sometimes less. 



THE USE or PARIS GREEN. 



In some districts of Kentucky Paris green has been in use for over 

 a decade. In the dark-tobacco districts of Kentucky and Tennessee 

 it certainly was used to some extent 10 years ago and at the present 

 time is in very general use. On account of the frequent injury to 

 tobacco by the use of this insecticide many farmers would not use it 

 if labor could be secured to do the hand-picking. On the whole, the 

 cost of the Paris green plus the cost of application, plus the loss 

 due to damaged tobacco, is much less than the cost of hand-worming. 

 In this district the use of insecticides has come to stay. It is a neces- 

 sity. 



Paris green is applied with a dust gun and without a carrier. 

 From 1 to 2 pounds per acre is the usual application ; 1 pound when 

 worms are small (i. e., less than half grown) and 2 pounds when 

 there are many worms over half grown. Success with the applica- 

 tion depends upon the judgment of the farmer in choosing the time 

 of application and upon the thoroughness with which the application 

 is made. Much of the tobacco that is injured by Paris green is in- 

 jured because of unevenness of application, or, what is too frequently 

 the case, because the grower has delayed the application until half- 



